\documentclass{standalone}
\usepackage{tikz}
\usepackage{ctex,siunitx}
\setCJKmainfont{Noto Serif CJK SC}
\usepackage{tkz-euclide}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{circuitikz}
\usetikzlibrary{patterns, calc}
\usetikzlibrary {decorations.pathmorphing, decorations.pathreplacing, decorations.shapes,}
\ctikzset{bipoles/length=1cm}
\begin{document}
\small
\begin{circuitikz}[>=latex, scale=0.8,european]
  % \useasboundingbox(0.9,0)rectangle(5.1,5);
  \draw [fill=blue!30] (-3.5,3)--(-3.5,0)--(3.5,0)--(3.5,3)--(2,3)--(2,1.5)--(-2,1.5)--(-2,3)--(-3.5,3);
  \draw [pattern=north east lines] (-3, .5) rectangle (-2.8, 3.2);
  \draw [pattern=north east lines] (3, .5) rectangle (2.8, 3.2);
  \draw [ultra thick] (-2.3, 3.2)node[above]{$A$}--(-2.3,.7);
  \draw [ultra thick] (2.3, 3.2)node[above]{$B$}--(2.3,.7);
  \draw (-2.3, 3.1) to[rmeter, t=V$'$] (2.3, 3.1);
  \draw (-2.9,3.2)--(-2.9, 4)--(-.5,4) to [european, pR,name=hb] (.5,4); 
  \draw (2.9,3.2)--(2.9, 4.5)--(2.9,4.5-|hb.wiper)--(hb.wiper); 
  \draw(-3, 3.1)--(-3.5,3.1)--(-3.5,5.2)to [rmeter, t=V] (3.5,5.2)--(3.5,3.1)--(3,3.1);
  \node at (-2.8,3.3)[left]{$+$};\node at (2.8,3.3)[right]{$-$};
  \node at (0,1){$E$};
\end{circuitikz}
\end{document}